Swimming pool drain

ABSTRACT

A sump for a swimming pool or spa includes a grate having an elongated slot for inflow of water at a low velocity high flow rate. A housing of relatively large capacity includes an outlet for conveying water to an oversized suction line to maintain the low velocity high flow rate to the junction with a conventionally sized standard suction line in fluid communication with a suction pump. A bypass line in fluid communication with the water in the pool or spa discharges water into the housing when the slot is sufficiently covered to prevent satisfying the flow rate into the suction line demanded by the pump and thereby prevent a level of suction at the slot sufficient to entrap clothing or a body part of a swimmer against the grate. The grate, a frame supporting the grate on the housing and the housing are devoid of elements that might cause entanglement of hair drawn into the sump. A hydrostatic valve may be coupled with the housing at locations of a pool or spa where the ground water level is sufficiently high to cause flotation of the pool or spa when partially filled or empty.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is related to the swimming pool drain disclosedin U.S. patent application entitled “POOL FLOOR DRAIN ASSEMBLY FOR ASUCTION-ACTIVATED WATER CIRCULATION SYSTEM”, assigned Ser. No.10/144,899 and filed May 14, 2002, which application is incorporated byreference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to drains for swimming pools and, moreparticularly to drains that will not permit entrapment of persons, theirclothing or their hair thereagainst.

2. Description of Related Art

Most swimming pools and spas, whether of concrete/gunite, fiberglass orhaving a vinyl liner above ground or in ground, include a drain at thelowest point. The purpose of the drain is to provide an outlet for flowof water from the swimming pool to the suction side of a pump. Theoutflow of the pump is passed through a filter to remove entrainedmatter. The filtered water is returned to the swimming pool at aboveand/or below water level outlets in the pool. Usually, the suction linefrom the drain includes a debris trap upstream of the pump to collectlarge sized debris.

The drain itself includes an apertured cover for passing watertherethrough but prevents the inflow of large sized debris as a functionof the size of the apertures or slots in the drain cover. A high flowrate of the water through the suction line is desirable to filter alarge quantity of water within a given time period to help maintainclarity of the water. A high flow rate through the drain cover can onlybe brought about by maintaining a high suction force beneath the draincover in order to draw water through the apertures of the drain cover.Such high suction force creates a potentially severe health hazard to auser of the pool or spa.

If a person were proximate the drain cover and a body part of the personcame close to the drain cover, the suction force present would tend todraw the body part against the drain cover. Once the drain cover iscovered by the body part, significant force by the person would berequired to move away from the drain. Particularly children and thosepersons physically enfeebled may not have the requisite strength orcapability to overcome the suction force acting upon them; as a result,they are likely to drown.

If a person in a swimming pool or spa wears loose clothing and comesinto proximity with the drain of a swimming pool or spa, the material ofthe clothing may be drawn into or cover the drain. In such event, thesuction force acting upon the material may be sufficient to prevent theperson from moving away from the drain. For persons with long full hair,the hair is readily drawn into the swimming pool/spa drain and may twistupon itself beneath the drain cover to the extent that extractionbecomes impossible. The potential consequences of both clothing and hairbecoming entrapped by the drain in a swimming pool or spa may be fatal.

SUMMARY OF THE INVENTION

A swimming pool or spa sump having a housing and a grate is providedwhich has low velocity, high volume waterflow into the suction line influid communication with a suction pump. The grate includes a singlerelatively large sized aperture or slot sufficient to permit debris topass therethrough and generally preclude more than partial insertion ofa swimmer's fingers or toes. The housing downstream of the grate isrelatively large sized and includes a large sized outlet incommunication with an oversized suction pipe ultimately connected to aconventionally sized suction line. An inlet to the sump is in fluidcommunication with a bypass line extending from, for example, an openingin the sidewall of the swimming pool or spa to provide an alternate flowpath into the sump in the unlikely event the grate were to besufficiently covered by a body part or clothing of a person to impedeflow into the sump sufficient to accommodate the rate of outflow throughthe suction line. For locations having a high level of ground water, ahydrostatic tube may be incorporated to permit flow of ground water intothe swimming pool and prevent an empty or near empty swimming pool fromfloating.

It is therefore a primary object of the present invention is to providea drain for a swimming pool or spa which will not entrap a personthereagainst.

Another object of the present invention is to provide a sump and grateattendant a drain for a swimming pool or spa that will permit easywithdrawal of an article of clothing or hair that may be drawn into thesump through the grate.

Another object of the present invention is to provide a high flow ratelow velocity drain for a swimming pool or spa.

Yet another object of the present is to provide a single apertured gratefor a swimming pool or spa drain sump.

Still another object of the present invention is to provide a sump for aswimming pool or spa drain having an outlet in fluid communication withthe suction line, an inlet in fluid communication with a bypass line andan inlet supporting a hydrostatic valve in fluid communication with thepool water.

A further object of the present invention is to provide a sump and grateadaptable for use in a concrete/gunite pool or spa, a fiberglass pool orspa or a vinyl lined pool or spa.

A yet further object of the present invention is to provide one of aplurality of configurations of a sump and a grate for use as a drain ina swimming pool or spa and having a large flow rate low velocity wateroutflow.

A still further object of the present invention is to provide a methodfor preventing the suction attendant the drain of a swimming pool or spafrom entrapping a person against the drain.

These and other objects of the present invention will become apparent tothose skilled in the art as the description thereon proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described with greater specificity andclarity with reference to the following drawings, in which:

FIG. 1 is a representative cross sectional view of a swimming poolincorporating the drain structure of the present invention;

FIG. 2 is a partial cutaway view of certain components of the sump;

FIG. 3 is a top view of the grate for the sump;

FIG. 4 is a cross sectional view of the sump;

FIG. 5 is a further cross sectional view of the sump;

FIG. 6 is a partial cutaway view of the concrete in which a firstvariant preformed sump is imbedded;

FIG. 7 is an exploded view illustrating major components of the sump;

FIG. 8 is a top view of the preformed housing embodied in the sump;

FIG. 9 is an isometric view of the bottom and side of the sump;

FIG. 10 is an isometric view of the interior of the sump;

FIGS. 11 and 12 illustrate mounting of the components of the sump toaccommodate different finish elevations of the bottom of the swimmingpool;

FIG. 13 illustrates a second variant configuration of a preformed sumpand FIG. 13A illustrates an end view thereof;

FIG. 14 is a top view of the sump shown in FIG. 13 and FIGS. 14A, 14Band 14C illustrate cutaway views thereof;

FIG. 15 illustrates a third variant of a preformed sump;

FIG. 16 illustrates a side view of the sump shown in FIG. 15;

FIGS. 17, 18 and 19 illustrate the fourth variant of a preformed sumpadapted for use with a swimming pool having a liner;

FIG. 20 illustrates a fifth variant of a preformed sump adapted for usein a swimming pool having a liner;

FIG. 21 illustrates a side view of the sump shown in FIG. 20;

FIG. 22 illustrates a top view of the sump shown in FIGS. 20 and 21;

FIG. 23 is a partial exploded view of the sump shown in FIGS. 20, 21 and22;

FIG. 24 is a further exploded view of a sump adapted for use in aconcrete pool;

FIG. 25 is an isometric view of the third variant shown in FIG. 24;

FIGS. 26 and 27 illustrate mounting of the components of the sump shownin FIGS. 24 and 25 to accommodate different finish elevations of aconcrete swimming pool;

FIG. 28 illustrates a sixth variant of a preformed sump;

FIG. 29 is a bottom view of the sump shown in FIG. 28;

FIG. 30 is an exploded view of the sump shown in FIGS. 28 and 29;

FIG. 31 illustrates a preformed cylindrical variant of the sump;

FIG. 32 is an exploded view of the sump shown in FIG. 31;

FIG. 33 is a partial cross sectional view of the sump shown in FIGS. 31and 32, and FIGS. 33A and 33B illustrate attachment of a pool liner tothe sump;

FIG. 34 illustrates the waterflow within the sump shown in FIGS. 31, 32and 33;

FIG. 35 illustrates a first variant of a preformed cylindrical sumpadapted for use in a swimming pool having a liner;

FIG. 36 is an exploded view of the sump shown in FIG. 35;

FIG. 37 illustrates the water flow in the sump shown in FIGS. 35 and 36;

FIG. 38 is a side view of the sump shown in FIGS. 35, 36 and 37;

FIG. 39 illustrates waterflow relief between the inlet and outletconduits attendant the sump shown in FIG. 35;

FIG. 40 illustrates a second variant of a preformed cylindrical sumpadapted for use in a swimming pool having a liner;

FIG. 41 is a partial exploded view of the sump shown in FIG. 40;

FIG. 42 is a further partial exploded view of the sump shown in FIGS. 40and 41;

FIG. 43 illustrates the components of a preformed seventh variant of thesump illustrated in FIG. 6;

FIG. 44 illustrates the grate usable with the sump shown in FIG. 43;

FIG. 45 is an exploded view illustrating a modification of the sumpshown in FIG. 43;

FIG. 46 is a cross sectional view of the sump shown in FIG. 45;

FIG. 47 is an exploded view of a modification of the sump shown in FIG.43;

FIG. 48 is a cross sectional view of the sump shown in FIG. 47;

FIG. 49 illustrates a preformed eighth variant of the sump shown in FIG.6; and

FIG. 50 is a partial cross sectional view of the sump shown in FIG. 49.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, there is illustrated a representative cross sectionof a swimming pool 10 having drain 11. The drain is formed in thecementitious material defining the pool and includes a sump 12 generallylocated at the low spot in bottom 14 of the pool. It is to be understoodthat the drain may be elsewhere in the bottom or in a wall of the poolor a spa. While the discussion below is primarily directed to varioussumps useable in swimming pools, these sumps could also be used in spasand the like. A preformed grate 16 is disposed and retained at the inletto the sump and incorporates one or more, but preferably one aperturefor inflow of water to the sump. A suction line 18 of relativelysubstantial diameter extends from sump 12. It is connected to aconventionally sized suction line 20 in fluid communication with aconventional debris trap 22. A further suction 24 extends from thedebris trap to the inlet in pump 26. Outflow from the pump throughreturn line 28 is channeled back into pool 10 in any one of severalconventional manners. The combination of suction lines 18, 20 and 24represent the suction lines for drawing water from the pool throughgrate 16 and sump 12. A bypass line 30 is in fluid communication withsump 12 and extends from the sump to a location in pool 10 remote fromgrate 16. Usually, an inlet 32 to bypass line 30 is disposed in a wallof the pool. Bypass line 30 serves in the manner of a relief line toprovide a source of water to sump 12 in the event grate 16 becomes fullyor partially blocked and thereby accommodates flow into suction line 18.It may be noted that outlet 34 of the bypass line is disposed at one endof sump 12 and inlet 36 of the suction line 18 is disposed at the otherend of the sump.

Turning to FIG. 2, further details of the sump and its relationship tothe pool will be described. Pool 10 may be formed in any of innumerableshapes and is usually either of cementitious or fiberglass material. Thepool shown in FIG. 2 is formed of cementitious material 38 definingbottom 14 of the pool and a sump 12 is formed within the cementitiousmaterial and illustrated as a block 40 to provide the requisite strengthand support for the elements associated therewith. It is to beunderstood that the sump could be formed in a wall of the pool. Suctionline 18, is sealed within block 40 with inlet 36 protruding into sump12. Similarly, bypass line 30 is sealed within block 40 with outlet 34located within the sump. A preformed frame 42 extends into sump 12 andincludes a circumscribing ledge 44 to secure the frame with thecementitious material defining the sump. Alternatively, a settingmaterial 46 may coat the sump defined by the cementitious material ofblock 40. In such event, frame 42 would be retained by the settingmaterial. Generally, most pools include a coating 48, usually plaster,which is applied to an elevation commensurate with top edge 50 of frame42. A preformed grate 52 is removably disposed within the frame 42(which grate is representatively identified by numeral 16 in FIG. 1). Asfurther shown in FIG. 3, grate 52 includes an elongated slot 54extending essentially for the full length of sump 12. The grate may beattached to frame 42 by screws 56, or the like, disposed at each corner.

Slot 54 is sized to accommodate the design flow rate for the suctionline. To accommodate large debris removal, the width of the slot is inthe range of about 1 to about 0.625 inches. Normally, the width of theslot should be limited to approximately 0.75 inches to prevent bodyparts, such as hands or fingers, from intruding very far into the sump.The length of slot 54 is variable and is a function of the design flowrate which is preferably 1.5 feet per second. For example, a drainsystem designed for a flow rate of 60 gallons per minute (GPM), a slotwidth of 0.75 inches will require a slot length of 17 inches to producea velocity of 1.5 feet per second through the slot. This results in arelatively low velocity of water flow through the slot and a very smallpressure drop in the chamber or housing of the sump. This low flowvelocity permits easy retrieval of hair or any clothing or part ofclothing that may have entered the sump or even the expanded suctionline downstream of the sump.

For reasons which will become apparent below, suction line 18 isoversized from that of the conventional size of pool suction lines.Preferably, the interior diameter of conduit 18 is sized to provide alow velocity water flow; a diameter of 4 inches would be representative.For example, the size should be sufficient to maintain a flow velocityof approximately 1.5 feet per second at a 60 gallons per minute (GPM)rate and this velocity will remain essentially constant to the junctionof suction line 18 with a much smaller and conventionally sized suctionline 20. Within suction line 20, the flow velocity may increase to 6feet per second, as is normal. The total length of low velocity flowfrom slot 54 in grate 52 to suction line 20 should be long enough toinsure that any length of hair a swimmer may have or length of clothingused by a swimmer and that may be drawn into the sump will not reachsuction line 20. Thereby, the “suction”acting upon such hair or clothingwill be relatively low and withdrawal of same is readily accomplished.By experimentation, it has been learned that a low velocity zone of 24to 30 inches in length provides ample protection to prevent a batherfrom becoming entrapped at the grate.

It is to be noted that each of the embodiments of the sumps describedherein is devoid of elements that might cause entanglement of long hairdrawn into the sump through the slot. That is, neither the grate, thesupporting frame nor the housing have any protrusions or slots aboutwhich strands of hair may wrap and thereby become impossible toextricate.

When pump 26 (see FIG. 1) is actuated, suction within suction line 18 istranslated into suction within sump 12. Because inlet 36 of the suctionline is close to one end of slot 54 in the grate, the flow from the poolwill be greatest at that end of the slot and diminish toward the otherend of the slot. Should slot 54 become blocked, the flow from the poolmay be reduced or even stopped. In such event, water will be drawnthrough bypass line 30 and this flow is discharged through outlet 34into the sump. Thereby, such bypass flow will satisfy the flowrequirements established by pump 26 and a high suction condition at slot54 is avoided. Thus, were a swimmer to fully cover the slot, entrapmentwould not occur as the suction present within sump 12 would be relievedby outflow of water through outlet 34. Moreover, the length of slot 54is unlikely to be completely covered by a swimmer which is not true withrespect to conventional circular or square inlets in drain covers.

FIG. 4 is a partial cross sectional view of the drain and itscomponents, as shown in FIG. 2. Setting material 46 seals the exteriorsurface of suction line 18 within the hollow representing sump 12disposed within cementitious material 40 defining bottom 14 of the pool.Frame 42 and its peripheral ledge 44 is lodged within and retained bysetting material 46 to locate top edge 50 of the frame essentiallycoincident with the exposed surface of coating 48 covering thecementitious material and defining the surface of the bottom of thepool. The frame includes a central opening 60 defined by an inwardlyextending peripheral flange 62. The flange provides support for grate 52and locates the upper surface of the grate coincident with the surfaceof bottom 14. As shown in this view, slot 54 is defined by two invertedU-shaped elements 64, 66 as illustrated. The lower end of slot 54 iscoincident with opening 60 to permit unimpeded flow through and out ofthe slot into sump 12. As illustrated in FIG. 3, screws or the like maybe used to retain the grate within a frame 42. It may be noted that theshape of U-shaped elements 64, 66 render the grate sufficiently robustto withstand any forces or weight that might normally by imposedthereon.

FIG. 5 is a further cross sectional view taken orthogonally to the viewshown in FIG. 4. The opposite ends of grate 52, along with thelongitudinal sides shown in FIG. 4, are supported upon flange 62 offrame 42. Elements 68, 70 define the ends of grate 52 and are formed inthe manner of inverted U's in cross section to provide the requisitestability and robustness. Arrows 72 generally illustrate the flow ofwater through slot 54 into inlet 36 of suction line 18. That is, most ofthe flow through slot 54 occurs proximate element 68 and the flow rateis reduced toward element 70. Under normal circumstances, little flow,if any occurs through bypass line 30 into sump 12 through outlet 34 fromthe pool as the flow through the grate satisfies the pump suctionrequirements.

Referring jointly to FIGS. 6, 7, 8, 9 and 10, there is shown a preformedsump 80 for lodgement in cementitious material 38 forming the shell ofthe pool. Sump 80 includes a hollow box like housing 82 having hollowbosses 84, 86 extending downwardly from bottom 88. Boss 84 isinterconnected with suction line 18 and boss 86 is interconnected withbypass line 30. As illustrated, boss 84 is of significantly greatercross sectional area than boss 86 in view of their very distinct anddifferent functions. Housing 82 includes a laterally expanded sides 90,92 defining interior ledges 94, 96. A peripheral flange 98 extendsoutwardly from housing 82 for mechanical locking engagement withcementitious material 38 surrounding sump 80. Thereby, the sump isimmovably mounted within the shell of the pool. A frame 42, like theframe discussed above, is slidably inserted through opening 100 at thetop of housing 82. To permit variation in the degree of insertion offrame 42 into housing 82, the frame includes a downwardly extendingperipheral wall 102. Ledge 44 encircles frame 42 for locking engagementwith the setting material or the coating, such as plaster, forming thesurface of the bottom of the pool. Grate 52 is like the grate discussedabove and slidingly mates with and is supported by the frame, asdiscussed above.

During installation, preformed sump 80 is set in place and secured tosuction line 18 and bypass line 30. Thereafter, cementitious material 38is poured thereabout in a conventional manner. As shown in FIG. 6, thecementitious material may extend upwardly at an angle to define a slope104 extending around housing 82. Thereafter, the space defined by thisslope may be packed with setting compound 106 in the conventionalmanner. Frame 42 is then inserted into the housing at a heightcommensurate with the surface of finish coating 48. As noted, wall 102forming a part of the frame permits significant vertical and cantingadjustment to insure that edge 50 of the frame is in the plane of thesurface of the coating. Grate 52 is placed within and secured to frame42.

Referring jointly to FIGS. 11 and 12, there are shown two versions ofinstallation of preformed sump 80 in a shell of a pool or spa formed ofcementitious material. Furthermore, a different version of a grate isillustrated and will be described. FIG. 11 illustrates locating thepreformed sump deeply within cementitious material 38 relative tofinished bottom 14 of the pool. To accommodate this depth, frame 42 israised with respect to housing 82 to locate its upper edge 50 in theplane of bottom of the pool. Grate 110 includes elements 112, 114 thatdefine slot 54. These elements extend longitudinally along the grate asdiscussed above.

Although not shown in detail, equivalent elements form the ends of slot54 as earlier described. Element 112 may include a lip 116 to close thegap with the side of frame 42. Element 114, like element 112, isgenerally in the shape of an inverted U. Furthermore, element 114 may beadapted to define a cavity 118 circumscribed by walls 120, 122, bottom124 and end walls. The purpose of this cavity would be to permitinsertion of finishing compound 126 to reduce the visual impact of thedrain.

In the installation configuration shown in FIG. 12, preformed sump 80 islocated within cementitious material 38 relatively close to bottom 14 incomparison to the installation shown in FIG. 11. Herein, frame 42 islowered into the housing to the extent that ledge 44 essentially restsagainst the top of sides 90, 92. Thereby, the interrelationship betweenframe 42 and housing 82 permits variation in depth of location of thesump without compromising locating the grate in the plane of bottom 14of the pool.

FIGS. 13, 13A, 14, 14A, 14B and 14C illustrate a second variantpreformed sump 130 having a housing 131 for receiving and supporting aframe 42 and a grate 52 discussed above. For the sake of brevity, onlythe differences between sump 130 and sump 80 will be described andcommon reference numerals will be used. At some locations, verticaldepth below the sump may be a problem on installation. Secondly, byminimizing the number of right angle flows, the debris coming throughthe drain will more readily pass and reduce the likelihood of clogging.And, it is less likely to entrap hair or clothing. Accordingly, thedischarge end of housing 131 includes an angled side 132 for supportingboss 84. The boss is connected to suction line 18 by suitable angledfittings. As depicted by arrow 134, the flow from the sump into boss 84and suction line 18 is more smooth than the flow attendant sump 80.Furthermore, it is likely that the rate of flow through slot 54 has alower gradient of flow rate from the end commensurate with boss 84 tothe end commensurate with boss 86. Moreover, such inclined orientationof boss 84 permits easier removal of debris that may have been drawninto suction line 18. As shown in FIG. 14C, grate 52 may include anupwardly open cavity 118 for receiving a finishing compound 126 tominimize the visually perceived presence of the elements of the sump inthe pool or spa.

FIGS. 15 and 16 illustrate a third variant of preformed sump 140, whichsump includes a housing 141 supporting frame 42 as discussed above alongwith a grate, such as grate 52 discussed above. Sump 140 may haveparticular utility in prefabricated pools wherein the pool wall/bottomis relatively thin and in pools having a liner. Housing 141 includes adownwardly extending section 142 for supporting boss 84 extendinghorizontally from side wall 144. The boss is connected in a straightline to suction line 18. At the other end of the housing, boss 86 mayextend downwardly from the bottom surface 146 and connected to bypassline 30. Alternatively, boss 86′ may extend horizontally from side 148of the housing. Boss 86′ would be connected in line with bypass line30′. By using horizontally extended bosses 84, 86′, the required depthbelow the pool bottom is minimized. As is evident from inspection, theflow into boss 84 would be similar to the flow illustrated in FIG. 13with regard to sump 130. As only one of bosses 86, 86′ would be used inany given installation, the unused boss would be capped. It is to beunderstood that variant sump 140 could be made with only one of bosses86, 86′.

FIGS. 17, 18 and 19 illustrate a fourth variant of preformed sump 150particularly adapted for use within a liner pool, whether above or belowground and wherein depth for the sump is a consideration. The sumpincludes a lower housing 152 and an upper housing 154 formed as aunitary structure. The lower housing supports boss 84 from a slantedside 156 in a manner similar to that of sump 130 shown in FIGS. 13 and14. Boss 86 extends horizontally from side 158. As shown in FIGS. 18 and19, boss 84 is in fluid communication with suction line 18 and boss 86is in fluid communication with bypass 30. Upper housing 154 is attachedto and extends from the top edges of lower housing 152 and defines aninternally extending peripheral ledge 160. A relatively thick peripheralflange 162 extends about the upper edge of housing 154. Ledge 160,whether formed as a part of the junction between housing 152 and housing154 or extending internally therefrom, serves the function of supportinga grate, like grate 52 described above. A rectangular ring 164 mateswith flange 162 and a plurality of screws 166 interconnect the ring withthe flange through corresponding apertures in the ring and holes in theflange, as is self-evident. A gasket 168 is lodged intermediate ring 164and flange 162. The pool liner is clamped between flange 162 and ring164 with gasket 168 serving to provide a leak free junction. Aperture170 in ring 164 is sized to accommodate insertion and withdrawal ofgrate 52 therethrough.

Variant sump 150 is installed in a depression extending downwardly intothe soil from the bottom of the hole defining the liner pool. Duringsuch installation, it would be connected to the requisite suction line18 and bypass line 30. Pool liner 174 is thereafter installed in thehole for the pool and would cover flange 162 at the upper end of housing154. Ring 164 would be placed in mating relationship to flange 162 andthe ring would be secured to the flange by a plurality of screws 166.The use of gasket 168 therebetween provides a seal against water leakageintermediate the liner and flange 162. Thereafter, the liner materialcommensurate with the opening to upper housing 154 would be cut away andgrate 52 would be inserted into housing 154. Screws, bolts or the like,may or may not be used to retain the grate in place. For an above groundliner pool, the sump would be supported in the conventional manner.

In some locations, the water table may be very close to groundelevation. When this is true, a swimming pool, when empty, may “float”and actually rise. Obviously, when such movement of the pool occurs theinterconnected structure is usually destroyed or at least severelydamaged. For this reason, many municipalities require the pools to havea hydrostatic valve to permit ground water inflow to the pool when thelevel of the water in the pool is below the ground water level.

Referring to FIGS. 20, 21, 22 and 23, there is shown a fifth variant ofpreformed sump 180 particularly adapted for use in a pool defined by aplastic liner lining a depression in the ground. Elements common withpreviously described sumps will be identified by common referencenumerals. Sump 180 is similar in certain respects with sump 150 shown inFIGS. 17, 18 and 19 as both are particularly configured for use withabove or below ground liner type pools. With such pools, it is usuallypreferable to minimize the depth to which the sump and attendantplumbing extends below the bottom of the pool.

Sump 180 includes a housing 182 having a sloping side 184 supportingboss 84. Suction line 18 is attached to and extends from this boss. Side186 of the housing supports boss 86 and bypass line 30 extendstherefrom. A second housing 190 extends above housing 182 and islaterally expanded to define ledges 192, 194, 196 and 198. End 200 ofhousing 190 is generally semicircular in planform and includes a bottomsurface 202. A hollow boss 204 extends downwardly from surface 202 andsupports a pipe 206 having a plurality of apertures 208 therein with thelower end being capped by a cap 210. A conventional hydrostatic valve212 is disposed in proximity to boss 204. A wall 214 extends fromsurface 202 upwardly to segregate the interior of end 200 from theremaining space in housing 190 (and housing 182). The top edge ofhousing 190 includes a peripheral lip 216 extending outwardly. A grate220 includes a slot 222 similar to slot 54 discussed above except thatit may be located along the center line of the grate, as illustrated.The grate is configured to have a flat end 224 for positioning adjacentwall 214 and a semicircular end 226 to conform with the interior ofsemicircular end 228 of housing 190. The grate is supported upon ledges192, 194, 196 and 198. A secondary grate 230 is semicircular in planformand includes a plurality of slots 231 disposed therein. This grate issupported within end 200 and adjacent wall 214.

When the water table beneath the pool rises a sufficient amount, waterwill flow into pipe 206 through apertures 208. The water flowing intoend 200 of housing 190 vents into the pool through slots 231 ofsecondary grate 230. Such flow is precluded by hydrostatic valve 212unless the pressure acting upon the valve by the water in the pool isless than the pressure of the ground water acting upon the valve. In thelater event, ground water will flow through slots 231 into the pool andfill the pool commensurate with the level of the ground water. Thereby,flotation of the pool is avoided. It is self-evident that when the poolis filled with water, no ground water will flow through hydrostaticvalve 212 and the pool will not become contaminated by the ground water.

It is to be noted that the assembly relating to the hydrostatic valve isphysically separated from the sump assembly and its operation. Access tothe hydrostatic valve is possible without disturbing the components ofthe sump. Moreover, it is hydraulicly isolated from the sump.

As particularly shown in FIG. 21, sump 180 is adapted for installationin a liner pool, whether above or below ground. Such installation willbe briefly described below. After the soil for the swimming pool hasbeen removed, a further depression is created at essentially the lowpoint and sump 180 is placed therein. Necessarily, suction line 18 andbypass line 30 are attached to the sump and pipe 206 extends downwardlyfor a distance into the soil. After installation of the sump at theappropriate location adjacent the bottom of the pool, a vinyl liner 232is installed in the normal manner and will cover the variant sump. Acollar 234 generally commensurate in width and shape with lip 216 isplaced upon the lip and secured to the lip by a plurality of screws 236.Thereafter, the material of the liner interior of the collar is cutaway. Grate 220 and secondary grate 230 are now installed in housing190.

FIGS. 24, 25, 26 and 27 illustrate a sump 240 very similar to sump 180described above except that sump 240 is intended for use in aconventional pool formed primarily of cementitious material, but couldbe installed in a pool made of fiberglass. Accordingly, the descriptionbelow will be primarily directed to the differences between sumps 180and 240; common reference numerals will be used for common elements.

Sump 240 includes a lower housing 242 having an angled surface 244 forsupporting boss 84 and suction line 18 attached thereto. End 246 of thelower housing includes a laterally expanded section one side of whichsupports boss 86 and bypass line 30 attached thereto. An upper housing250 of generally oval shape, as illustrated, has a lateral widthessentially coincident with expanded section 248 of the lower housing.Ledges 252, 254 and 256 interconnect the upper housing with the narrowedsection of the lower housing, as illustrated. End 258 of the upperhousing is generally semicircular and extends beyond end 246 of thelower housing and includes a panel 260 for supporting hollow boss 204supporting pipe 206 extending therefrom and hydrostatic valve 212associated with the boss. A circumferential ledge 262 extends laterallyfrom about upper housing 250.

Referring primarily to FIG. 24, frame 270, grate 272 and secondary grate274 will be discussed. The primary function of frame 270 is that ofpositioning the upper surface of grate 272 and secondary grate 274 in aplane commensurate with the bottom of a pool. Accordingly, frame 270 isvertically positionable and to some extent cantable as necessary toachieve alignment of the grate with the pool bottom. Frame 270 includesa skirt 276 having an exterior dimension essentially coincident with theinterior vertical surface of upper housing 250. At the lower mostposition of the frame, it may rest upon ledges 252, 254 and 256. A panel278 extends downwardly from the frame at a location to place itessentially adjacent wall 280 (see FIG. 25). Furthermore, the width ofpanel 278 is essentially coincident with the distance between the sidesof lower housing 242 at expanded section 248 and the width of the wallsof upper housing 250. Thereby, panel 278 essentially segregates thespace defined by end 258 from the remaining interior surface of the sumpirrespective of the vertical position of frame 270 relative to the sump240. A peripheral ledge 282 extends about frame 270 for mechanicalengagement with setting material upon installation in a pool. Aninternally extending ledge 284 is coincident with the bottom edge offrame 270 and includes a cross member 286 extending across the frame; itdelineates the semicircular end 288 of the frame to leave the spacebetween this section and the curved wall of the skirt with an openbottom.

Grate 272 includes a slot 290 extending generally along the center lineand dimensioned as discussed above. Skirt 292 of the grate isdimensioned to have a close fit within frame 270 up to semicircular end288 and wall 294 of the grate terminates essentially coincident withcross member 286. Thereby, wall 294 in combination with the interiorsurface of end 288 forms the equivalent of a semi-cylindrical space.Secondary grate 274 covers this semi-cylindrical space but providescommunication from therein through slots 296. Bosses disposed withinframe 270 may be used to support the secondary grate. Alternatively,legs may extend downwardly from the secondary grate to bear against theledge at the lower end of the frame and thereby support the secondarygrate.

The installation of further variant sump 240 will be described withprimary reference to FIGS. 26 and 27. During construction of the poolfrom cementitious material 38, variant sump 240 is lodged therein spacedapart from expected finished bottom 14. Ledge 262 surrounding upperhousing 250 provides a mechanical lock with the cementitious materialand movement of the sump is prohibited. It may be noted that suctionline 18, bypass line 30 and pipe 206 are secured to their respectivebosses prior to formation of the cementitious material about the sump.Preferably, the cementitious material extends upwardly at an angle awayfrom ledge 262. After the cementitious material has cured, frame 270 isinserted within the upper housing at a height and at a cant such thatits top edge 300 is essentially coincident with finished bottom 14 ofthe pool. Setting material 106 and the coating 48 are laid around theframe to encase and mechanically lock ledge 282 of the frame with thesetting material. Thereafter, grate 272 and secondary grate 274 areinserted within the frame.

As may be noted from FIG. 26, sump 240 is closer to bottom 14 than issump 240 shown in FIG. 27. This difference in height is readilyaccommodated by raising or lowering frame 270 with respect to the upperhousing and such vertical movement can be carried out to the extent ofthe depth of skirt 276; moreover, as is true with the frames discussedand to be discussed, the frame can be somewhat canted to accommodatealignment with the bottom of the pool. Operation of sump 240 isessentially equivalent to that described above with respect to sump 180and need not be repeated herein.

A sixth variant sump 310 is illustrated in FIGS. 28, 29 and 30. Thissump is very similar to sump 240 with two major differences. First, thissump is curved or arcuate. Second, bypass line 30 enters the sump at thebottom rather than along a side. Because of the similarity of thecomponents of sump 310 with sump 240, and the fact that installation isequivalent within the cementitious material of a pool, the descriptionbelow will be relatively cursory.

An arced housing 312 includes a lower housing 314 having an expandedsection 316 and interconnected with an upper housing 318. A ledge 320interconnects the lower housing with the upper housing and serves as asupport for frame 322 when the frame is at its lower most point relativeto housing 312. Lower housing 314 supports boss 84 from an angled sideand supports boss 86 from the bottom surface at the end of the housingopposite from boss 84. End 324 of upper housing 318 extends beyond wall326 of lower housing 314 and defines a semicircular cavity having afloor or panel 328. Boss 204 is supported by and extends from panel 328for interconnection with the hydrostatic valve assembly. Frame 322includes a panel 330 which is inserted within expanded section 316adjacent wall 326 upon mating of the frame with the housing 312 to forma relatively closed compartment within end 324 irrespective of thevertical position of the frame relative to the housing. A ledge 332extends about frame 322 to mechanically secure the frame relative to thesurrounding cementitious material (or setting material) of the pool uponinstallation. As noted with respect to sump 240, the height of the framerelative to the housing is a function of the location of the housingrelative to the finished bottom of the pool in order to locate top edge334 of the frame essentially coincident with the surface of the bottomof the pool. Frame 322 includes an internal ledge 336 and a cross member338 for supporting grate 340 to be placed within the frame; it alsoprovides strength to the frame. Grate 340 includes a curved or arcuateslot 342 extending for essentially the full arcuate length of the grate.Skirt 344 of the grate is dimensioned to mate with the interior surfaceof the frame and is of a depth commensurate with the distance from topedge 334 of the frame to ledge 336 in order to place the top surface ofthe grate essentially in the plane defined by top edge 334. The grateincludes a wall 346 that rests upon cross member 338 in the frame anddefines a semi cylindrical cavity within the corresponding end of theframe. Grate 340 may be secured to frame 322 by screws 352 penetratingholes 354 and into engagement with the corresponding parts of ledge 336,cross member 338; other means for attaching the grate may be used. Asecondary grate 348 is disposed within the frame adjacent wall 346 ofgrate 340 and the interior wall of the frame. One or more slots 350 areformed in the secondary grate to provide fluid communication from boss204, through end 324 of housing 312, the corresponding end of frame 322and through the slots. Thereby, any ground water flowing through thehydrostatic valve associated with boss 204 will flow directly into thepool as panel 330 extending from the frame essentially precludes flow ofsuch water into housing 312 and the conduits associated therewith. Ifthe hydrostatic valve is not needed, boss 204 can be capped.

Installation of sump 310 in the cementitious material forming the poolis equivalent to the installation procedure discussed above with respectto sump 240.

Referring jointly to FIGS. 31, 32, 33 and 34 there is shown acylindrical sump 360 embodying the gist of the present invention. Asthere are certain elements of this sump which are common with elementsin the previously described sumps, common reference numerals will beused for such elements. A cylindrical housing 362 supports boss 84 fordischarging water into radially expanded suction line 18 and suctionline 20. Bypass line 30 is connected via boss 86 to the housing. It isto be understood that housing 362, boss 86, boss 84 and necked downsuction line 18 can be manufactured or assembled as a single unit foruse in the field. A pipe 206, having apertures 208 for admitting groundwater, extends from boss 204 located at the center bottom of housing362; this pipe can be made as part of the housing also. An inflow ofwater, as represented by arrow 364 swirls about grate 366 and flows intocircular slot 368. Slots 370 in cap 372 accommodate outflow of groundwater into the pool.

Cylindrical sump 360 is intended for use with a liner pool. Hence, arepresentatively illustrated sheet 374 of vinyl is illustrated. It is tobe understood that cylindrical sump 360, along with the attendant waterlines, would be located in the dirt beneath the vinyl sheet if the linerpool is an in-ground pool.

The interior construction of cylindrical sump 360 will be described withreference primarily to FIGS. 32, 33 and 34. A vertical wall 376 extendsradially inwardly from interior surface 378 of cylindrical housing 362.A cylinder 380 includes an interior circular flange 382 for attachingthe cylinder to bottom 384 of the housing with screws 386 or the like. Avertical radially outwardly extending wall 388 extends from cylinder 380into contacting engagement with the interior edge of wall 376. Thereby,circular flow about cylinder 380 is essentially precluded. It may benoted that the location of walls 376, 388 are intermediate bosses 84, 86and their associated openings in the housing. Cap 372, and itsassociated slots 370, is in sealing engagement with the top of cylinder380. A ring 390 rests upon circular ledge 392 disposed interior ofhousing 362 and below top edge 394 thereof. Alternatively, it may besecured to the interior surface of housing 362, as shown in FIGS. 33Aand 33B. A further ring 396 is secured to ring 390 by screws 397 or thelike penetrably engaging holes 398 in ring 396 and threadedly engagingholes 400 in ring 390. It is to be understood that vinyl sheet 374 (seeFIGS. 31, 33A and 33B) is disposed intermediate these two rings and thatthe vinyl sheet is clamped in place by the rings. It may be noted thatthe elements of the clamps are interior to the external surface ofhousing 362. To ensure a sealed engagement with the liner, an annulargasket may be used in the conventional manner. After clamping, theportion of vinyl sheet interior of the rings is cut away.

A shroud 402 includes a circular skirt 404 depending from a ring element406. Upon installation of shroud 402, the skirt defines an annular spacebetween it and the exterior cylindrical surface of cylinder 380. Theshroud may be secured in place by screws 397 as shown on the right inFIGS. 33A and 33B. Thereby, slot 368 illustrated in FIGS. 31, 33A and33B is formed. As particularly shown in FIGS. 31 and 34, the suctionpresent within boss 84 draws water from within housing 362. The flowpath of this water is downwardly through slot 368 with most of the waterbeing drawn through the slot counterclockwise from wall 376, as depictedby arrow 364 in FIG. 31 and arrows 408 shown in FIG. 34. Thereby, theflow rate demanded by suction pump 26 (see FIG. 1) is fully satisfiedand little, if any, water will be drawn through boss 86 from bypass line30 to satisfy the waterflow demand present at the outlet to boss 84.However, should slot 368 be covered to a greater or lesser degree,sufficient low pressure would exist at the inlet to boss 86 to causewater to flow clockwise within housing 362 to satisfy the demand at theinlet to boss 84. As noted previously, in the event the liner pool isempty and the level of ground water approaches that of the bottom of thepool, the hydrostatic valve attendant boss 204 will open and groundwater will flow through cylinder 380 and slots 370 in cap 372 and intothe pool to prevent the pool from floating.

FIGS. 35, 36, 37, 38 and 39 illustrate a variant cylindrical sump 410.Elements common with previously described embodiments will be referencedwith the same reference numerals. This cylindrical sump is also intendedto be used with a liner pool, as indicated by vinyl sheet 374 in FIG.38. Housing 412 includes a bottom 414 supporting an elbow 416 to whichboss 84 is attached and an elbow 418 to which boss 86 is attached. Boss204, attendant pipe 206 and a hydrostatic valve, also extends frombottom 414. Aperture 420 in bottom 414 is in fluid communication withelbow 416. Aperture 422 is in fluid communication with boss 204.Aperture 423 is in fluid communication with elbow 418. A verticallyextending shroud 424 includes a cylindrical section 426 to define anannular space 428 intermediate the cylindrical section and interiorsurface 430 of housing 412. A further section 432 is coincident with apart of the edge of aperture 420. A still further section 434 iscoincident with a part of the edge of aperture 422. A wall 436 extendsfrom the junction of sections 432, 434 to surface 430 of housing 412.Thereby, any flow within housing 412 between aperture 420 and aperture422 must be through annular space 428. The upper edge of housing 412includes an radially extending circular lip 438 having a plurality ofholes 440 spaced there along. A ring 442 is generally coincident withlip 438 and includes a plurality of holes 444. This ring is used toclamp the sheet of vinyl against lip 438; screws 446 may be used topenetrably engage holes 444 and threadedly engage holes 440 in the lip.An annular gasket may be used to ensure a sealed junction with the sheetof vinyl. As noted above, the vinyl sheet interior of ring 442 iscutaway.

A further shroud 450 includes a recessed apertured plate 452 having anaperture 454 generally coincident with the interior edges of sections426, 432 and 434 of shroud 424. A plurality of holes 456 in plate 452are coincident with each of a plurality of holes 458 formed in the topedge of shroud 424 to secure shroud 450 with shroud 424 by screws 460penetrating the respective pairs of holes. Shroud 450 includes a firstsection of a cylindrical skirt 462 having a radius to place it radiallyoutwardly of section 426 of shroud 424. Vertical walls 464, 466 aredisposed at the terminal ends of skirt 462. Slot 470, as primarilydepicted in FIG. 35, is formed by skirt 462, walls 464 and 466 andinterior surface 430 of housing 412. Thus, slot 470 is formed by aplurality of separate but joined elements.

A cap 472 includes a plurality of slots 473. This cap is placed adjacentto plate 452 in the depression formed by downwardly extendingcylindrical wall 474. The cap may be retained in place by screws 475penetrably engaging holes 476 and threadedly engaging holes 477 in plate452. In the event the hydrostatic valve associated with boss 204 isopened due to an empty pool and a rising ground water level, the waterwill flow upwardly through aperture 423 through shroud 424, aperture 454in plate 452 and into the pool through slots 473. It may be noted thatthere is no intentional fluid communication between any water inflowthrough the hydrostatic valve and either of apertures 420, 422 in thebottom of housing 412.

As depicted by arrow 478 in FIG. 37, water will flow into slot 470through annular space 428 and into elbow 416 through aperture 420. Theprimary draw for this waterflow will be toward the counterclockwise endof slot 470 as it is in closest proximity to aperture 420 and there willbe little flow of water through aperture 422 into cylindrical sump 410from bypass line 30.

As particularly illustrated in FIG. 39, elbows 416 and 418 are adjacentone another in contacting relationship. By forming apertures 479 a, 479b at the point of contact, a limited amount of waterflow therebetweenwill occur which will have no effect upon operation of the variantcylindrical sump. This waterflow is used as part of the pressure testprocedure prior to final installation to ensure that the plumbingattendant the sump is leak free. Thereby, a single pressure test can bemade.

Referring jointly to FIGS. 40, 41 and 42, there is shown a variantcylindrical sump 480 which is quite similar to cylindrical sump 410except that the internal shrouds are differently configured with certainother changes of elements. Because of such similarity, only thedifferences will be described in detail and common elements will havecommon reference numerals.

A shroud 482 is configured similarly to shroud 424 of sump 410 exceptthat it extends only part way upwardly from bottom 484 of cylindricalhousing 492. Shroud 482 includes a cylindrical section 486 that definesan annular space 488 with interior surface 490 of housing 492. Section494 is partly coincident with the aperture in bottom 484 in fluidcommunication with elbow 418 and boss 86. Section 496 is partlycoincident with the aperture in bottom 484 in fluid communication withelbow 416 and boss 84. A wall 498 interconnects the junction of sections494 and 496 with interior surface 490 of housing 492. Shroud 500, asparticularly shown in FIG. 42, includes a ring like plate 501 defining aslot 502 which is an arcuate section. A cylindrical shroud 504 extendsfrom plate 500. It may be noted that the diameter of the plate measuresless than the internal diameter of housing 492. A section 486A mateswith section 486. Similarly, sections 494A and 496A mate with sections496 and 494, respectively. Wall 498A mates with wall 498. A wall 506interconnects shroud 504 and section 486A to define one end of slot 502.Similarly, a wall 508 interconnects with shroud 504 and an extension 510of section 486A to define the other end of slot 502. A further wall 511extends laterally from shroud 504 coincident with a corresponding partof wall 498 within housing 492.

As shown in FIG. 41, plate 501 includes an aperture defined by the topedges of sections 486A, 494A and 496A. A ring 512 includes a pluralityof holes 514 mating with holes 516 in radially extending lip 518 ofhousing 492. A plurality of screws 520 secure ring 512 to lip 518 andthe vinyl sheet disposed therebetween. Furthermore, ring 512 maintainsshroud 500 in place as the ring includes a radially inwardly extendinglip 513 for supporting the perimeter of the shroud. A cap 522 includesone or more slots 524 in fluid communication with the aperture definedby sections 486A, 498A and 496A. The cap may be secured to shroud 500 byscrews 526 penetrably engaging holes 528 and threadedly engaging holes529.

In certain installations, it may be important to minimize the depth of adrain sump below the bottom of the deep end of a pool. Referring jointlyto FIGS. 43, 44, 45 and 46, there is illustrated a sump particularlyconfigured to meet such requirement and yet provide the benefitsdiscussed above. In particular, the large cross-sectional area of thesuction line of sufficient length to prevent passage of a part of anarticle of clothing or of long hair into the conventional sized suctionline is contained completely within the sump. This permits attachment ofthe conventionally sized suction line directly to a boss of the sump orto other junction element. Certain of the elements illustrated anddescribed herein are equivalent to similar elements of previouslydescribed sumps. These elements will be identified by common referencenumerals. If required by the site of the installation, a hydrostaticvalve can be added to the sump.

Sump 530 is primarily a box or housing 532 open on the top. A peripheralledge 534 extends about the top somewhat below top edge 536. Boss 84 isin fluid communication with the interior of housing 532 through anaperture 538. As discussed above, boss 84 is in fluid communication withan enlarged suction line 18. Boss 86 is in fluid communication with theinterior of housing 532 through an aperture 540; the boss is connectedto bypass line 30, as described above. A frame 542 includes a skirt 544extending into the interior of housing 532 in mating relationshiptherewith. The frame includes a peripheral ledge 546. A further interiorperipheral ledge 548 extends inwardly to support a grate 550. The grateincludes a slot 552 disposed along one side opposite to the sideadjacent to aperture 538 in housing 532. The configuration of the slotmay be as described above. The grate may include a receptacle 554adjacent the slot. The purpose of this receptacle is to permit a workmanto fill the space with plaster or other finishing material used tofinish the bottom of the swimming pool. Thereby, only minor elements ofsump 530 will be visible to a user of a pool. For identificationpurposes, this plaster is identified by numeral 556. Alternatively, thereceptacle may be omitted and a sheet of plastic may be formed laterallyof the slot to the corresponding edges of the grate. As particularlyillustrated in FIG. 44, only relatively thin elements of the grate willbe apparent to a user of the pool as the bulk of the surface within theperimeter of the grate appears to be of a material and a color the sameas that surrounding the grate.

Whenever any sump of the types described herein is installed, thepiping/conduits associated therewith must be pressure tested prior tofinal completion of ensure that there are no leaks. Such pressuretesting is generally performed by plugging the outlet in the sump to thepump and the inlet in the sump for the bypass line. Thereafter, pressuretesting is conducted. This is common practice and well known to thoseskilled in the art. Although not specifically described with respect tothe previously disclosed sumps, the opening attendant bosses 84 and 86would normally include internal threads to permit threaded attachment ofplugs. Such threaded attachment is illustrated in FIG. 43. Inparticular, threads 558 are associated with aperture 538 and threads 560are associated with aperture 540. It is to be understood that similarstructure would exist for the previously described and to be describedsumps.

As particularly shown in FIGS. 45 and 46, the flow path from slot 552 toaperture 538 attendant boss 84 can be lengthened by incorporating ashroud 562. Thus, the total length of the above described largecross-sectional area suction line can be wholly contained within sump530. Because of the requirement for pressure testing, at least uponinstallation of sump 530, shroud 562 must be removable prior to suchtesting in order to have access to aperture 538 and the shroud must beattachable subsequent to such testing. As illustrated, the shroud isprimarily a sheet of plastic having two planar sections 564 and 566joined to one another by a curved section 568 to place the planarsections orthogonal to one another. A lip 570 extends along the bottomedge of section 564 to permit attachment to the bottom of box 532 byscrews or other attachment means. The edge of planar section 566 restsupon a shelf 572 formed in the housing. With such shroud, a flowgradient will occur along slot 552 in that most of the flow will betoward the end of the slot proximate the opening of the shroud andlesser flow will occur at the other end of the slot adjacent thejunction of the shroud with wall 574 of the box. With such installationof shroud 562, the suction line attached to sump 532 may be ofconventional cross-sectional area and the length of low velocity flowfrom grate 550 will not be compromised.

As particularly shown in FIG. 46, sump 530 may be mounted withincementitious material 580 forming the shell of the pool. The upper endof housing 532 is generally left free of cementitious material, asindicated by lines of demarcation 582, 584. Thereafter, setting material586 is laid to envelope ledge 534 and a mechanical bond is formedtherewith to solidly mount housing 532. Frame 542 is inserted withinhousing 532 to a depth commensurate with the top edge 588 of the framebeing essentially in the plane corresponding with bottom 14 of the pool.It is understood that a layer of plaster or coating 48 provides thefinished surface at the bottom of the pool. As discussed above,receptacle 554 of grate 550 may be filled with plaster 556 to minimizethe color/texture discontinuity of the grate and the adjacent plastersurface. As illustrated, ledge 546 of frame 542 is enveloped withsetting material 586 and plaster 556 may also be in contact therewith tofirmly lodge the frame in place.

FIGS. 47 and 48 illustrate a further variant sump 590, which sump issimilar to sump 530 except for the channeling of water into boss 84.Accordingly, these differences will be primarily reviewed below. Forcommon elements, common reference numerals will be used. To increase theflow path of water entering through slot 552 to boss 84, a shroud in theform of a tube 592 is attached to and extends from wall 574 of housing532 in generally overlapping relationship with the opening of boss 84.This tube serves the same function as shroud 562 discussed above and thesuction line attached to boss 84 may be of conventional cross-sectionalarea without compromising the benefits of low velocity flow.Installation of sump 590 is essentially duplicative of the installationfor sump 530, as shown in FIG. 48. Accordingly, a duplicativedescription is not necessary.

Referring jointly to FIGS. 49 and 50 there is illustrated a furthervariant sump 600 particularly adapted for use in a pool or spa made of afiberglass shell and disposed below the bottom of the pool or spa. Sump600 includes a housing 602 having a boss 84 extending from end 604. Boss86 extends from opposite end 606. The illustrated plate 608 is a part ofthe pool/spa shell and includes an aperture 610 dimensioned tocorrespond with the interior dimensions of housing 602. During lay up ofthe pool/spa shell, housing 502 and bosses 84 and 86 may be layed upcommensurate therewith. Thereby, at the time of installation of thepool/spa, a workman need only attach the suction line and the bypassline to bosses 84 and 86, respectively.

After installation of the pool/spa at the site, frame 612 is insertedinto housing 602 through aperture 610 and retained in place by nubs 614engaging corresponding depressions 616 disposed at each corner ofaperture 610. The frame includes a shelf or ledge 618 extendinginternally at the bottom of the frame. A grate 620 includes a slot 622of the type described above. The grate is dimensioned to slide intoframe 612 and rest upon ledge 618 of the frame. Thereby, slot 622provides a channel for water from the pool/spa to flow into housing 602and thereafter into boss 84. It is to be understood that sump 600 may bemounted in a pool formed of cementitious material or in a pool having aplastic liner. In the latter event, various mounting procedures wellknown to those skilled in the art would be employed.

1. A sump for use in a swimming pool or a spa, said sump comprising incombination: a. a housing having an open upper end; b. an outletdisposed in said housing; c. an oversized suction line interconnectingsaid outlet with a conventionally sized suction line; d. an inletdisposed in said housing coupled to a bypass line in fluid communicationwith the water in the swimming pool or spa; e. a grate having a singleelongated slot disposed therein for inflow of water to said housing; andf. a frame for interconnecting said grate with said housing.
 2. The sumpas set forth in claim 1 including a hydrostatic valve and conduitcoupled with said housing.
 3. The sump as set forth in claim 1 whereinsaid outlet and said inlet are disposed at opposed ends of said housing.4. The sump as set forth in claim 1 wherein said outlet an said inletare disposed in the bottom of said housing.
 5. The sump as set forth inclaim 1 wherein said housing includes a sloping wall and an end andwherein said outlet and said inlet are disposed in said wall and saidend, respectively.
 6. The sump as set forth in claim 1 wherein saidhousing includes a wall and wherein said outlet and said inlet arecoupled in said wall of said housing.
 7. The sump as set forth in claim6 including a shroud extending from a location proximate said wall atleast partially surrounding said outlet for channeling water to saidoutlet.
 8. The sump as set forth in claim 7 wherein said shroud isdetachably attached to said housing.
 9. The sump as set forth in claim 1wherein said housing is rectangular.
 10. The sump as set forth in claim1 wherein said housing is cylindrical.
 11. The sump as set forth inclaim 1 wherein said housing is arcuate.
 12. The sump as set forth inclaim 1 including a ledge extending laterally at least partially aboutsaid housing.
 13. The sump as set forth in claim 1 wherein said frameincludes a skirt for insertion within said housing.
 14. The sump as setforth in claim 1 wherein said frame includes a ledge extending laterallyat least partially about said frame.
 15. The sump as set forth in claim14 wherein said frame includes a skirt for insertion within saidhousing.
 16. The sump as set forth in claim 1 wherein said frameincludes a ledge for supporting said grate.
 17. The sump as set forth inclaim 1 wherein said grate includes a pair of opposed end walls fordefining the length of said slot.
 18. The sump as set forth in claim 1wherein said grate includes a pair of opposed side walls for definingthe width of said slot.
 19. The sump as set forth in claim 18 whereinsaid grate includes a pair of opposed end walls for defining the lengthof said slot.
 20. The sump as set forth in claim 2 including asegregated compartment within said housing in fluid communication withsaid hydrostatic valve.
 21. The sump as set forth in claim 20 includinga secondary grate disposed at the upper end of said compartment foraccommodating a flow of water from said hydrostatic valve into the poolor spa.
 22. The sump as set forth in claim 1 wherein the flow rate ofwater through said slot is 1.5 feet per second and the volumetric flowrate is 60 gallons per minute.
 23. The sump as set forth in claim 1wherein said oversized suction line is configured to accommodate a watervelocity rate of 1.5 feet per second and a flow rate of 60 gallons perminute.
 24. The sump as set forth in claim 23 wherein said oversizedsuction line is approximately 4 inches in diameter.
 25. The sump as setforth in claim 1 wherein the distance of water flow from said grate tothe conventionally sized suction line is not less than 20 inches. 26.The sump as set forth in claim 25 wherein the distance of the water flowfrom said grate to the conventionally sized suction line is in the rangeof about 24 inches to about 30 inches.
 27. A method for draining waterfrom a pool or spa through a sump in fluid communication with a suctionpump via a suction line and a bypass line in fluid communication withthe water in the pool or spa, said method comprising the steps of: a.drawing the water to be drained through a grate having a singleelongated slot; b. conveying the water from the slot into a housing; c.an oversized section of the suction line having an opening in thehousing and the step of further drawing water from the housing into theoversized suction line; d. further conveying the water from theoversized suction line to a junction between the oversized suction lineand a conventionally sized suction line and through the conventionallysized suction line to the pump; and e. providing fluid communicationbetween the water in the pool or spa through an inlet in the housing influid communication with the bypass line.
 28. The method as set forth inclaim 27 wherein said step of drawing is carried out at a velocity of1.5 feet per second.
 29. The method as set forth in claim 28 whereinsaid step of drawing is carried out at a flow rate of 60 gallons perminute.
 30. The method as set forth in claim 27 wherein said step offurther conveying is carried out within the oversized suction line is ata velocity of 1.5 feet per second.
 31. The method as set forth in claim30 wherein said step of further conveying is carried out at a flow rateof 60 gallons per minute.
 32. The method as set forth in claim 27including the step of selectively introducing ground water into the poolor spa through the housing upon actuation of a hydrostatic valve.
 33. Amethod for installing a sump in a pool or spa having a suction line anda bypass line, said method comprising the steps of: a. establishing ahousing with the material defining a wall of the pool or spa; b.attaching a frame to the housing at a height relative to the housing tolocate the top of the frame substantially in the plane of the wall ofthe pool or spa; c. securing a grate having a single slot in the frame;d. interconnecting a length of an oversized suction line with thehousing to convey water from the housing to a conventionally sizedsuction line; and e. further interconnecting the bypass line with thehousing.
 34. The method as set forth in 33 including the step of formingthe housing from the material defining the wall of the pool or spa. 35.The method as set forth in 33 including the step of forming the housingfrom cementitious material defining the wall of the pool or spa.
 36. Themethod as set forth in 35 including the step of stabilizing the locationof the frame with setting material placed adjacent the cementitiousmaterial.
 37. The method as set forth in 33 including the step ofsecuring a preformed housing with the material defining the wall of thepool or spa.
 38. The method as set forth in 33 wherein the pool or spaincludes a liner and including the step of securing the frame to theliner.
 39. The method as set forth in 33 including the step ofintroducing ground water through the housing into the pool or spa uponactuation of a hydrostatic valve.
 40. A sump for use in a pool or spa,said sump comprising in combination: a. a preformed housing having anopen top, an outlet and an inlet; b. a frame for engaging said open topof said housing; c. a grate having a single slot; and d. a ledgedisposed within said frame for supporting said grate.
 41. The sump asset forth in 40 wherein said frame includes a depending skirt forslidably engaging the interior of said housing.
 42. The sump as setforth in 40 wherein said frame includes a laterally extending ledge forengagement by material surrounding said sump to retain said frame infixed relationship to said housing.
 43. The sump as set forth in 40wherein said slot extends for substantially the full length of saidgrate.
 44. The sump as set forth in 40 wherein said housing includes abottom and wherein said outlet and said inlet are disposed in saidbottom.
 45. The sump as set forth in 40 wherein said housing includes apair of opposed end walls and wherein said outlet is disposed in one endwall of said pair of end walls and wherein said inlet is disposed in theother end wall of said pair of end walls.
 46. The sump as set forth in40 wherein said housing includes a pair of opposed end walls and whereinboth said outlet and said inlet are disposed in one end wall of saidpair of end walls.
 47. The sump as set forth in 46 including a shrouddisposed in said housing and extending from about said outlet toward theother end wall of said pair of end walls.
 48. The sump as set forth in47 wherein said shroud is a cylinder.
 49. The sump as set forth in 47wherein said housing includes a bottom and a pair of opposed side wallsand wherein said shroud comprises a pair of joined sections extendingfrom said bottom to one side wall of said pair of side walls.
 50. Thesump as set forth in 40 wherein each of said housing, said frame andsaid grate are rectangular in plan form.
 51. The sump as set forth in 40wherein each of said housing, said frame and said grate is circular inplan form.
 52. The sump as set forth in 51 wherein said slot is arcuate.53. The sump as set forth in 40 wherein each of said housing, said frameand said grate is arcuate in plan form.
 54. The sump as set forth in 53wherein said slot is arcuate.
 55. A sump for use in a pool or a spa,said sump comprising in combination: a. a cylindrical housing having abottom; b. an outlet and an inlet in fluid communication with saidhousing; c. a further inlet disposed in said bottom; d. a spaceextending from said bottom defined by a plurality of sectionssurrounding said further inlet; e. a passageway adjacent the interiorsurface of said cylindrical housing and in fluid communication with saidinlet and said outlet; f. a wall extending from said plurality ofsections to the inside surface of said cylindrical housing, said wallbeing disposed intermediate with said inlet and said outlet; g. a shroudfor attachment to the upper end of said cylindrical housing, said shroudincluding a slot in fluid communication with said passageway and anaperture in fluid communication with said space; and h. a cap secured tosaid shroud and disposed at the top of said space, said cap including atleast one slot disposed therein.
 56. The sump as set forth in 55including a suction line connected to said outlet, a bypass lineconnected to said inlet and a hydrostatic valve connected to saidfurther inlet.
 57. The sump as set forth in 55 wherein the pool includesa liner and a ring attachable to said cylindrical housing for capturingthe liner between said ring and said cylindrical housing.
 58. The sumpas set forth in 55 wherein said slot is arcuate.
 59. The sump as setforth in 55 including a first elbow connected to said outlet, a secondelbow connected to said inlet, a first aperture disposed in said firstelbow, a second aperture disposed in said second elbow, said firstaperture being in fluid communication with said second aperture.